The second fire reported to have broken out at Unit 2 of the Fukushima Daiichi nuclear power plant in Japan is no longer visible and the effort to inject sea water into Units 1, 2 and 3 are currently on-track as radiation levels are back down.

Japanese sources also report that the evacuation of all residents within 20 kilometers of the plant has been completed successfully.

But a new cause for concern has surfaced as a drop has been observed in the coolant level of Unit 5. Even if this reactor, along with Units 4 and 6, is completely shut down, the nuclear fuel must still be kept cool and the plan is to use an operational diesel generator from Unit 6 to refill the water in Unit 5.

The first AST Modular data storage container at the Thor Data Center, Iceland. Controlled by ABB AC500 PLCs, the data center is cooled by free outside air instead of by conventional energy-hungry chillers.Credit: ABB